The Church of England faces a tense summer as it wrestles with the divisive issues of women bishops and gay clergy, a senior official said yesterday.

William Fittall, the secretary general of the general synod, the church's legislative body and national assembly, said a combination of public debates, a breakaway Anglican conference and the clash between conservatives and liberals was giving Christians cause for concern.

"There is no doubt that we are at an unsettled moment in the Church of England," said Fittall. "This was always going to be a big summer. [The] Lambeth [conference of bishops] is a big event in the wider communion and the fact that it is considering women bishops goes to the heart of what kind of church we want to be. The weekend's story has caused further anxiety on the part of many."

He was responding to the Bishop of London's decision to order an investigation into the "marriage" last month between two gay priests, the Rev Peter Cowell and the Rev David Lord, who exchanged rings and vows at St Bartholomew the Great church in the City of London.

A statement issued by the bishop of London, the Right Rev Richard Chartres, said services of public blessings for civil partnerships were not authorised.

Rows about gay clergy and women bishops have long threatened the unity of the Anglican communion and the fellowship of the Church of England will be put under pressure next month, when the ordination of women bishops will dominate the agenda of the synod meeting in York. Its 476 members will spend seven and a half hours debating the issue over four days.

Fittall said: "This is going to overshadow the whole of synod. This is going to be the issue that is there throughout and the whole of synod is a bit anxious because nobody is confident about what the outcome will be. It is genuinely hard to call."

A motion from the house of bishops suggests a code of practice, which would mean rescinding the Episcopal Ministry Act of Synod 1993. Annulling this act, which promised provision for those opposed to women priests, is seen by some as a move that could split the church. There will be special arrangements for those unable, as a matter of conviction, to receive the ministry of women as bishops or priests, but opponents fear they will not be enough.

The first female clergy were ordained in 1994 and the historic event led to £27.4m in compensation being paid out to clergy who left as a result. Out of 512 who left, 72 returned. There are no proposals for similar financial arrangements in the future.

Church figures show there are more than 18,000 clergy in the Church of England, and 1,500 people are currently in training for ordained ministry. Although the first woman bishop will not be ordained before 2014, conservative groups are talking about an exodus. Stephen Parkinson, director of Forward in Faith, said "if push came to shove" half of the group's 1,000 members, all clergy, would leave.

"We do not want to leave but the church is not doing enough to accommodate people like us. The 500 clergy work in the roughest, toughest parishes of inner cities, so there would be an exodus from the places that need the most help."

He described the house of bishops motion as "brinkmanship", saying: "I believe they will change their minds and they will be more generous. They're just seeing what they can get away with."

The Church of England has yet to follow the example of the 15 Anglican and Episcopalian provinces around the world that have voted for, and in some cases ordained, women bishops.

Scotland and Ireland have approved women bishops but have yet to appoint one. Earlier this year Wales voted against legislation proposed by the Archbishop of Wales, Dr Barry Morgan, that made provision for traditionalists, with senior figures preferring to wait and pass legislation that made no special arrangements.

Morgan said he was "deeply disappointed" with the result. "It is an issue that is not going to go away or be ignored," he said. "The Church in Wales will have to grapple with it. I am sad that we have to go through the whole process again."

The Archbishops of Canterbury and York, Dr Rowan Williams and Dr John Sentamu, support the consecration of women, yet both favour a compromise that satisfies both camps. In a carefully worded presidential note following the house of bishops meeting, they said: "Diverse views are held with deep and passionate conviction and there is a general acknowledgement of the cost involved in every option. Communications have spelled out the different sorts of cost - to our sense of continuity, our mission to the nation, our confidence that we can find coherent and just patterns for our life as a church."

The two men described next month's debates as "something of a watershed" for allowing synod members to discuss, for the first time, the approach it wished to take regarding legislation.

If the synod votes in favour at its meeting in York next month, the legislation would have to be approved by parishes, deaneries and dioceses before going to the parliamentary ecclesiastical committee, then the Commons and Lords.

View of a deaconess

The Very Rev Vivienne Faull, 53, dean of Leicester, was ordained as a deaconess in 1982:

"My job is challenging, exciting and I enjoy the variety of demands and experiences. As opportunities for women have developed, in the church and in society, we have grown and responded. So have institutions. My gender is not an issue and that is a huge change - but changing an institution is more difficult than changing someone's mind.

"As I'm at the heart of writing legislation on women bishops I've been having many discussions for the last 20 years, but they have moved on in tone and subtlety. I've experienced encounters where people have thought I'm less of a person in the sight of God. It is not confined to gender. The discussions now are more creative and profound; I find it more intellectually challenging and fulfilling.

"Do I want to be a bishop? I don't know. There are sacrifices bishops have to make on private life. You have to count the cost - every woman does. But if I was asked, I would consider it."